Nocentelli MMR Fuzz

Description for this outide-the-box-thinking fuzz circuit is up at freestompboxes with the original schematic. Seems rather nice.

Hornby Skewes Zonk Machine I

Well got time for another study break, so it's that time for another layout. Just like the last layout I posted, here's another uber rare fuzz, a gift from the fuzz gods that no worshiper of fuzz should be without IMHO.

One of the more famous Tone Bender MKI influenced fuzz boxes and now almost as legendary as its golden cousin was the John Hornby Skewes Zonk Machine. A little more wacky in the graphics department, but not as heavy duty or robust as the MKI, the Zonk Machine was almost identical in its circuitry. Made between 1965 and 1966 in Leeds, England, the Zonk Machine like the MKI was only made in small numbers before the pedal was updated with a more modern and easier to produce unit.

Layout 1: Original PNP

Layout 2: Original NPN

Some suggested gains and tips I found over at DIYSB:
Q1=53hfe
Q2=126hfe
Q3=98hfe

Q1=70hfe,
Q2=116hfe
Q3=97hfe
 
One suggestion with the leakage:
Q1=180hfe/.142ma
Q2=176hfe/.177ma
Q3=195hfe/.124ma

Values taken from an Original Unit
Q1=TI AO2 650 Hfe= 180, leakage= 0.12mA.
Q2=Mullard OC75 Hfe= 78, leakage= 0.29mA
Q3=OC44 Hfe= 58, leakage= 0

Tips for other builders interested in the Zonk Machine:

1. Socket all transistors because you’re likely to go through a bunch of them before you find some that work well.

2. The Zonk is very bright. Play around with the input cap and try values between .001uF and .01uF. Maybe even set up a three way switch to toggle between different values.

3. Definitely use a log/audio taper “Fuzz” pot. I used linear at first but it greatly limits the useful range of the pot. The name “Fuzz” is a bit of a misnomer as it doesn’t really fulfill most people’s definition of a fuzz control. It essentially adjusts the bias of Q2. The Sola Sound Tonebender Mk1, which is a topographically identical circuit (sans the 33K resistor), called this pot “Attack” which is a bit more appropriate IMO.

4. Set up an SPST switch to bypass the 2.2M resistor for nasty, all-out craziness!

5. Some came with 25k Log Fuzz pot, and 220k resistor instead of 470k.

Hornby Skewes Shatterbox

The Hornby Skewes Shatterbox is another stupid rare fuzz/booster made in the 60's, need I really say any more? In case I do, info is not really available on this monster, but here's what I found:

Skewes Shatterbox Produced in Leeds circa 1966, the unit combines two effects; The JHS Zonk fuzz and a Treble Booster circuit, the original unit was produced in exceptionally limited numbers and was famously used by Mark Bolan T-Rex.

Layout 1: Original PNP

Layout 2: NPN Version

Layout 3: Original with LED

Layout 4: NPN with LED

 

Way Huge Purple Platypus

Not a lot of info on this one, so here is what I found out about it:

Uber Rare Way Huge Purple Platypus Octidrive only about 120 or so made. Essentially, this is a Red Llama Overdrive and an octave effect similar to the Green Ringer.  A very specialized pedal,  its best use is to push your already driven amp into fuzz while doubling up on the upper octave. Discontinued way back in the late 90's, and no reissue set for release.

I will add one more thing. On the schematic from over at FSB there's a 27k resistor that seems to go nowhere coming off Drive 1. I've looked over the PCB a million times, and despite the thought it has to go somewhere I'm certain it's a dead end. Maybe to make a possible tracing more difficult.

BYOC Crown Jewel

Here is a layout for the BYOC Crown Jewel (minus the boost).
The boost is an independent circuit of your choice in serie with the main circuit.
There is also an extra switch to select if you want the boost "Pre" or "Post" the main  circuit.
You can find all infos and schematic on their website here.